This invention relates to an improved construction of, and a method of constructing, the main assembly of an automotive engine type of water pump. Such pumps are used for circulating the coolant fluid, that is, the water and anti-freeze mixture, used in automotive-type engines.
An engine water pump essentially consists of a rotating shaft, which has an impeller mounted on one end and a drive gear or connection on the other end, all arranged within a sealed housing. The housing includes an enlarged impeller chamber within which the pump impeller is positioned. The shaft passes through a bearing contained within the housing. A seal arranged around the shaft between the impeller and the bearing prevents the leakage of coolant between the impeller chamber and the bearing. Coolant is directed into the impeller chamber where it is pumped, by the impeller, out through an outlet so that it moves through the automotive engine passageways for cooling the engine. The drive gear end of the pump shaft is driven by a suitable power take-off from the engine, such as through a gear system, or belt system or the like.
Typically, the housing for the main assembly of the pump is made of a casting, as for example, an aluminum die casting. The housing is formed of a roughly cylindrical body portion which widens at one end into the impeller chamber. The body portion is ordinarily constricted at about its middle to form two sections. A pump seal is inserted in one section and a ball-type bearing, with an exterior race, is arranged in the other section. Inner races for the balls may be formed by providing grooves in the pump shaft so that the balls are confined between the grooves in the shaft and the external race. Additionally, suitable sealing rings are installed or formed in situ around the bearing race for sealing it against the interior of the housing.
Generally, the conventional main assembly is assembled within the housing by applying the bearing parts upon one end of the shaft, inserting the shaft and bearing into one end of the housing, and then applying the seal and the impeller, upon the opposite portions of the shaft and into the opposite end of the housing. That is, for assembly, the parts are installed through both ends of the housing. That assembly is relatively time-consuming to accomplish and consequently, expensive. In addition, the housing, the bearing and the systems used for sealing the bearing to the housing are relatively expensive parts which require considerable labor to produce. A considerable amount of machining is required to finish a number of the surfaces in order to obtain the accuracy necessary in the finished pump.
Thus, the invention herein is concerned with an improvement in the bearing construction by which the pump parts may be assembled from one direction into the housing, rather than from both directions, and wherein the bearing and the bearing seal arrangement are considerably simplified to eliminate a considerable portion of the previously required machining and assembly operations. In addition, the invention is concerned with forming a main pump assembly which is of lesser weight than that previously used.